1. Field of the Invention
The present invention relates to a zoom lens and an imaging apparatus. More specifically, the present invention relates to the technical field of a zoom lens that is suitable for use in photographic optical systems such as digital still cameras and video cameras, and achieves miniaturization and ensures high image-forming performance while providing a blur correction function, and an imaging apparatus including the zoom lens.
2. Description of the Related Art
In recent years, there has been a proliferation of imaging apparatuses using a solid state imaging device, such as digital still cameras. The proliferation of imaging apparatuses such as digital still cameras has created a demand for taking lenses, in particular, zoom lenses that are compact and offer high image-forming performance.
For zoom lenses, a blur correction function that optically corrects image blur caused by camera shake or the like during shooting has been widely adopted. In the case of interchangeable-lens digital cameras, in particular, it is desired that these zoom lens be equipped with a blur correction function while ensuring miniaturization of the lenses.
There are many kinds of zoom lenses used for digital still cameras. Among those, a type of zoom lenses having a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power, which are arranged in order from the object side to the image side, is widely available as a lens type that is suited for miniaturization.
Many kinds of schemes as described below exist as image blur correction schemes for this type of zoom lens.
For example, there exist a scheme which performs blur correction by moving the entire third lens group in a direction perpendicular to the optical axis (see, for example, Japanese Unexamined Patent Application Publication No. 2003-228001), and a scheme which performs blur correction by moving a plurality of lenses in the third lens group in a direction perpendicular to the optical axis (see, for example, Japanese Unexamined Patent Application Publication No. 2009-282439). Also, there exists a scheme in which a negative lens group is provided in a fourth lens group and a positive lens group is provided in a fifth lens group, and which performs blur correction by moving the entire fourth lens group in a direction perpendicular to the optical axis (see, for example, Japanese Unexamined Patent Application Publication No. 2008-152190).